This invention relates generally to optoelectronic transceiver modules and in particular, it relates to an optoelectronic transceiver module, and its method of manufacture, whereby the module is inexpensive to manufacture, has a small yet robust package, provides for static discharge, and can be installed and replaced via a ribbon style connector.
Optoelectronic transceiver modules provide for the bidirectional transmission of data between an electrical interface and an optical data link. The module receives electrically encoded data signals which are converted into optical signals and transmitted over the optical data link. likewise, the module receives optically encoded data signals which are converted into electrical signals and transmitted onto the electrical interface.
Normally, the transceiver is mounted onto one of the circuit card assemblies of a host computer, input/output system, peripheral device, or switch. Therefore, as with all electronic equipment, there is a need for a transceiver having an outer package design which occupies as little circuit card surface area as possible.
In addition, there is a need for a transceiver module which is highly reliable and durable. One method presently used to ensure reliability and durability is to encapsulate the electronics of the transceiver within an insulative potting material. Encapsulating the transceiver electronics results in reducing vibration sensitivity and prevents unauthorized personnel from meddling with the module's electronics.
Presently, the molding of the potting material around the transceiver electronics is performed by placing the electronics within a silicone mold. Any portion of the electronics which extends outside of the mold is caulked, by hand, with a silicone compound which provides for a liquid tight seal. Once the mold is sealed, potting material is inserted therein. After the potting material is allowed to cure, the silicone mold is peeled away from the newly formed module.
The above described prior art molding process has several drawbacks. For example, it is time consuming and results in a transceiver module which has a pitted outer surface. In addition, the silicone mold used in the molding process has a limited life of only three to five modules before a new mold must be employed.
The optoelectronic module is provided with a plurality of electrical pins for forming an electrical connection with a circuit card assembly. The electrical pins consist of solid wire strands with each pin having one end connected to the electronics within the module and the other end protruding from the module's potting material.
The portion of each pin which protrudes from the potting material is either soldered within a plated through-hole, which is provided by the circuit card assembly, or placed within a connector which grasps onto the pin. However, the flimsy wire pins are very susceptible to deformation during both the normal handling of the module and its removal and installation onto a circuit card assembly. Thus, the flimsy pins currently used in the prior art are difficult and time consuming to attach to a circuit card assembly since they must be periodically inspected and realigned. Furthermore, the pins may break if they are realigned too many times.
In addition to the electrical pins, the module also is equipped with two mounting ports for physically securing the module onto the circuit card assembly. The module is placed onto the circuit card assembly so that the mounting ports align with holes provided in the circuit card assembly. Once the module is properly aligned, screws are inserted through the holes in the circuit card assembly and into the mounting ports of the module. The screws are then tightened until the module is firmly affixed to the circuit card assembly.
Similarly, to remove the module from the circuit card assembly, the screws must be removed and the wires either unsoldered from the circuit card or pulled from the connector which is a timely and expensive process requiring multiple components.
Finally, once the module is secured to the circuit card assembly, optical fibers contained within an SC duplex plug connector are mated to the module. Normally, the SC duplex connector has a plastic housing which may be statically charged. Thus, its connection onto the transceiver module may result in damage to the electronic components within the module unless proper grounding of the SC connector is provided.
It should be appreciated by those skilled in the art that the possibility of damage due to static discharge is not only applicable to transceiver modules which mate with an SC duplex connector. Other optoelectronic modules, such as, for example, Gigabaud Link Modules (GLM), are also susceptible to static discharge damage whenever they are mated to a connector containing optical fibers.
Therefore, there is a need for a transceiver module which provides for a small, yet robust package, which is inexpensive to manufacture, provides for static discharge, and can easily and quickly be installed and removed from a circuit card assembly. The present invention is such an apparatus.
Likewise, there is a need for preventing a statically charged fiber optic connector from damaging the electronics within an optoelectronic module.
In view of the above, it is an object of the present invention to provide a small transceiver module package.
It is another object of the present invention to provide a module package that has a robust and tamper resistent design.
Also, it is an object of the present invention to provide a module which can quickly be installed and replaced from a circuit card assembly.
Another object of the present invention is to provide a module package design that can quickly and easily be produced.
A further object of the present invention is to provide a module package that can be produced inexpensively.
It is yet another object of the present invention to prevent a statically charged connector from damaging the electrical circuitry within an optoelectronic module by pre-grounding the plug connector.
Furthermore, it is an object of the present invention to provide a module with a coating which dissipates an electrostatic discharge and serves as an electromagnetic shield.